ESTRO 2024 - Abstract Book

S958

Clinical - CNS

ESTRO 2024

Histopathologically confirmed GSM patients who received treatment at eight European institutions were included and retrospectively analyzed.

Results:

We included 159 patients with a median follow-up time of 8.6 months. The majority received surgery (94.3%), postoperative radiotherapy (pRT, 78.6%), and temozolomide (TMZ)-based postoperative chemotherapy (65.4%). The median overall survival (OS) and progression-free survival (PFS) were 12.0 and 6.1 months, respectively. At 6-month, 1-year and 2-year, OS was 72.5%, 50.8% and 22.1%, while PFS was 51.5%, 24.8% and 8.3%. In the multivariable Cox regression analysis (MVA), the following factors were significantly associated with OS: age (hazard ratio (HR): 1.03, p=0.008), subtotal resection (STR) vs. biopsy only (HR: 0.06, p<0.001), gross total resection (GTR) vs. biopsy (HR: 0.06, p<0.001), pRT vs. no RT (HR: 0.37, p=0.016), postoperative TMZ-based chemotherapy vs. no chemotherapy (HR: 0.37, p=0.001), MGMT promoter status non-methylated vs. methylated (HR: 2.46, p=0.004), and MGMT promoter status unknown vs. methylated (HR: 1.90, p=0.017). Secondary GSM, TP53 mutational status, and tumor size were not significantly associated with OS. For PFS, the following factors were significantly associated in the MVA: Tumor size (HR: 1.21, p=0.008), STR vs. biopsy only (HR: 0.15, p=0.007), GTR vs. biopsy only (HR: 0.14, p=0.004), postoperative TMZ-based chemotherapy vs. no chemotherapy (HR: 0.35, p<0.001), MGMT promoter status non-methylated vs. methylated (HR: 2.58, p=0.001). Formally, age (HR: 1.02, p=0.052) and pRT (HR:0.50, p=0.055) were not significantly associated with PFS. Secondary GSM and TP53 mutational status were not significantly associated with PFS.

Conclusion:

Aggressive trimodal therapy comprising surgical excision, pRT and TMZ-based chemotherapy remains essential for oncological outcomes, while smaller tumor size, younger age and methylated MGMT promoter status are associated with improved survival.

Keywords: Gliosarcoma, multicenter analysis, outcomes

2971

Digital Poster

Outcomes of radiosurgery with CyberKnife in patients with multiple brain metastases.

Agnieszka Lewandowska, Adam Deja , Łukasz Raszewski, Krystyna Adamska

Greater Poland Cancer Centre, Radiation Oncology Department III, Poznań, Poland

Purpose/Objective:

The purpose of this study is to evaluate the survival and irradiated volumes of healthy brain tissue in patients with a minimum of four brain metastases, who have undergone treatment with CyberKnife. Assessment of the value and limitations of GPA scale used in patients with brain metastases was presented in this paper.